I was told that they almost always go bad from a problem with how the engine is running. My passenger side cat sounds like it has rocks tumbling around inside it sometimes so I assume its come apart inside and was wondering if anyone else has had the same situation and known what caused it. The guy who did my exhaust said its either running rich or lean, hell if I know but my injectors on that bank make a lot of noisy ticking if that means anything, more so than the drivers side bank anyways. My first things to check would be the plugs and wires, but the thing is Ive never heard of anyone else blowing out a cat from something that simple. Should I replace the cat and assume it was just a bad cat or is it more likely my motor had somethign to do with it? BTW it is a carsound magnaflow 3" high flow cat.

 

Yes, that is how cats can go bad. I've had that same thing happen on 2 stock cats and I recently heard from someone else about a similar experience with a carsound cat. (I've had two of these by the way, and I really liked them)

A cat won't necessarily go bad because of the engine. It may have been damaged during shipping (a crack formed during a drop, which eventually evolved into a bigger problem) or install. It may have been a factory defect to begin with, who knows. I would just get it replaced since they're so cheap.

They can also go bad both when an engine is running too rich or too lean, but I doubt that is your problem.

 

Thank you for the advice and I dont think my car is running badly. Would it not have to be running VERY rich or lean to blow out a cat in 2 days? I got mine shipped for 59 bucks off e-bay

 

welll now I think its the motor... the other cat just blew out, and when I say they blew I mean little fragments of the honeycomb ceramic crap in the cats along with the fuzzy stuff blows out when I start the car and rev and obviously drive it and it sounds like the cats were replaced with rock tumblers. My car sounds different now lol so they are pretty gutted. I DO however have a ported maf sensor that is pretty black with dirt... but that might not make the car run so lean the cats blow out like that let alone the first cat in 3 days. what about o2 sensors? How do I determine if they are bad? Everythign seems fine on datamaster not sure how you diagnose with that unless something trips a trouble code. What about a MAP sensor? any other sensors I should check out? Yes they are cheap cats but at 60 bucks plus 35 bucks install for both thats more than I can afford to waste by a long shot... I only make 1000 a month Inspection is in february

BTW: I was going to clean the sensors with electrical component cleaner and put some stock maf ends. I also have 2 o2 sensors off a 94 trans am that have 73k miles on them that have been sitting doing nothing for 3 years I could try out if it could be the o2 sensors..